OPTIMIZATION AND PERFORMANCE EVALUATION OF SEQUENTIAL liATCH REACTOR FOR TREATMENT OF PETROLEUM REFIENRY WASTEWATER

Abstract

Petroleum refineries are generally considered a major source of pollutants in areas where they are located and are regulated by a number of environmental laws related to air, land and water. At present most of the refineries has trickling filter/activated sludge process as the secondary treatment process which require hung installation cost, large installation area and high maintenance thus it require some modification in the process so that all these deficiencies can be eliminated. The present study deals with the modification in the conventional wastewater treatment facility of a petroleum refinery. Sequencing batch tr, reactor (SBR) is the promising alternative among the other biological processes. SBR is the next age of activated sludge process; these are time based process as compare to the conventional area based processes. This study is about the design, modeling and the laboratory scale research on the optimization of SBR for the treatment of petroleum refinery wastewater. The effect of operating parameters, which include mixed liquor suspended solids concentration (MLSS), ratio of React phase to settle phase and the aerated fill & unaerated fill. The parameters taken under consideration during the study were COD, BOD and Phenol concentration. The results revealed that chemical oxygen demand (COD) and Biochemical oxygen demand removal efficiency were improved and lies in between 94-97% and 96-97% respectively. The treatability of SBR towards phenol, which is one of the most hazardous compound emitted by refineries was also very good but not up to the mark set by pollution control board. To achieve the concept of zero discharge in the petroleum refinery and to enhance the performance of SBR to remove phenol completely the biological system was club with adsorption with the use of bagasse fly ash (BFA) and activated carbon commercial (ACC) grade as an adsorbent which increases phenol removal efficiency up to 99.3% and also improves the settleability of sludge. The control of the sludge bulking and excessive growth of filamentous bacteria is restricted by taking the precautionary steps such as sludge wasting. The settling characteristics were measured in terms of SVI and Settleability curve. The filterability of the sludge was also estimated. The physico-chemical characterization of excess sludge wasted was done to evaluate its utilization as a source of energy.